Joined: May 2019
||Posted: 10 July 2019,10:14
Thanks for all the suggestions.
I have clocked the blades for runout on the motor axle, so this will show any warping. Some are slightly warped with 0.2mm runout radially.
I have also checked runout linearly across the blade. This was initially very very bad, 0.7mm! This caused a lot of issues to start with.
I have since shimmed the motor to get it square to the bridge rails to within 0.1mm.
The machine is capable of making pefect cuts, with a nice new blade. It can cut a slither off a 1200mm tile to 0.4mm variation - pretty good I think.
I am fairly confident that the machine runs true.
It's the blades that are trying to cut off line.
Once the blade starts to go off, you can see it ping back into line at the end of the cut when the offcut is released from the tile.
If you run the blade along the edge of an new tile, which is dead square and straight, it tracks the edge perfectly.
If you run the blade along the egde of a tile this it's just cut, off line, you can see the cut gradually getting further and further from the side of the blade.
I think that the egde of the blade is not wearing evenly for some reason and on a long cut this is enough to give is a bias to the left or right.
I have since worked out how to regrind the edge of the blades to get them square instead of rounded and this seems to help a lot. It involves spinning the blade in a pillar drill while grinding the edge with an angle grinder, edge on at 90 degrees.
I have probably ruined a couple of blades, as cutting with them, when they are flexing sideways so much probably warps them.
I have 5 blades to play with. 3 from ATS (cheap). 1 Rubi TVH, (a little more expensive) and 1 from Marcrist. (Expensive).
They all exhibit this issue eventually, the Marcrist kept going the longest.
I have send the Marcrist blade back to them for analysis along with a tile to test.
I think this porcelain is particularly hard and very non abrasive so the blade needs a lot of dressing between cuts to keep the diamonds exposed.
Montolit have suggested a blade for this type of Porcelain, needless to say it's 6 times more expensive than the ATS blades, but maybe it will cut 10 times longer! I'll wait to see how I get on with the blades I have until I pull the trigger on a £180 blade.
I've checked the machine very carefully with dial gauges, squares etc. I am confident it runs true now.
The blades never get warm and I let them cut at their own pace.
You can tell the tile is hard on the blade as the first cut goes through like butter. After one or two more cuts, you can feel there is slightly more resistance. After a load of cuts, the blade takes 3 times longer to get through the tile.
Sorry for the long post, but hopefully there is some light at the end of the tunnel and I have a lot more tiles to cut. I've made a bit of a rod for my own back by using a different layout pattern, so I need to 'make' two smaller tile sizes from the really large 1200x600 tiles that I'm not using any more.